Alli weight-loss pill: Does it work?

Alli (pronounced AL-eye) is an over-the-counter drug meant for overweight adults who are struggling to shed excess pounds. With its easy access and weight-loss promises, is Alli your answer to losing weight?

What is Alli?

Alli is the reduced-strength, 60-milligram version of orlistat (Xenical), a 120-milligram prescription drug.

Xenical is approved for use by people who have a body mass index (BMI) of 30 or more (obese), as well as people with a BMI of 27 to 29 (overweight) who have other health risk factors such as high blood pressure or diabetes.

Alli is approved for over-the-counter sale — with some exceptions — to overweight adults 18 years and older. Both Alli and Xenical are meant to be used as part of a weight-loss plan that includes a low-calorie, low-fat diet and regular physical activity.

What are the concerns with Alli?

In 2010, the Food and Drug Administration (FDA) published a safety review of orlistat because of rare reports of serious liver injury in people using it. The FDA found no evidence to confirm that orlistat was the cause of the reported liver injuries.

However, Alli and Xenical labels were revised because of the reports. Talk to your doctor immediately if you have signs or symptoms that may indicate liver injury:

Itching

Loss of appetite

Yellow eyes or skin

Light-colored stool

Brown urine

How does Alli work?

Lipase, an enzyme found in the digestive tract, helps break down dietary fat into smaller components, so it can be used or stored for energy. Alli inhibits the work of lipase. When you take the drug with a meal, about 30 percent of the fat you consume isn't broken down and is eliminated through bowel movements.

How much weight could I lose using Alli?

Alli may help you lose weight, but the weight loss will likely be modest — perhaps just a few pounds more than you would lose with diet and exercise alone.

In a 2014 review of clinical trials, researchers assessed the effect of weight-loss pills in studies that were at least one year long. People who ate a calorie-restricted diet, exercised regularly and took Alli lost an average of 5.5 pounds (2.5 kilograms) more in one year than did people who only dieted and exercised.

About half the people taking Alli while following a calorie-restricted diet and increasing physical activity lost 5 percent or more of their body weight within a year. Clinically meaningful weight loss — enough weight loss to begin lowering the risk of cardiovascular disease, diabetes and other diseases — is generally defined as 5 percent or more of body weight.

Legal Conditions and Terms

Reprint Permissions

A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.